In flat panel displays (e.g., backlight computer displays), light-management film(s) (which can also be referred to as a sheets, layers, foils, and the like) are commonly used, for example, to direct, diffuse, and/or polarize light. For example, in backlight displays, a light-management film comprising a light-redirecting structure, which can also be referred to as a brightness enhancement film, can direct light along a viewing axis (i.e., an axis normal (perpendicular) to the display) using the light-redirecting structure (e.g., a prismatic structure). This enhances the brightness of the light viewed by the user of the display and allows the system to consume less power in creating a desired level of on-axis illumination. Such films can also be used in a wide range of other optical designs, such as in projection displays, traffic signals, and illuminated signs.
In making and/or handling the light-management film comprising the light-redirecting structure(s), various defects can be imparted to the light-management film. The light-redirecting nature of the light-management film can make inspection of these defects in the light-management film difficult. For example, the light-redirecting nature of the light-management film can cause unfocused images (e.g., blurred images, distorted images, and the like). Typical inspections by either human or cameras are not thorough enough to reliably capture all relevant defects in a given light-management film sample. This includes inspecting the film under a restricted (limited) set of viewing and lighting angles.
What is needed in the art is an improved system and method for inspecting a light-management film. More particularly, what is needed in the art is an improved system and method for inspecting a light-management film comprising a light-redirecting structure.